As tool changers to be employed for various apparatuses, for example, industrial robots, those including a male member to be attached to the robot side and a female member to be attached to the tool side are disclosed (for example, Patent Literature 1). In these tool changers, upon a cam in the male member being engaged with an engaging member in the female member in a state in which a projection portion provided in the male member is inserted in a coupling hole in the female member, the male member and the female member are coupled. Also, disengagement between the cam and the engaging member enables decoupling between the male member and the female member. In such a manner as above, a tool changer enables change of tools attached to an industrial robot.
Depending on the purpose of use of the robot or the type of the tool, it is necessary to transmit/receive, e.g., control signals between a circuit such as a controller provided on the robot body side and a circuit incorporated in the tool. Where a tool changer is used, the robot body and the tool are coupled/decoupled, and thus, it is necessary to connect/disconnect signal wires between the circuits according to the coupling/decoupling. Signal relay devices that perform such connection/disconnection of signal wires are known. A signal relay device includes signal modules attached respectively to a male member and a female member. The signal modules include respective connectors that, upon the male member and the female member being coupled, cause respective terminals to come into contact with each other and thereby electrically connected, and upon the male member and the female member being decoupled, cancel the contact between the terminals.